Teaching and learning astronomy in the 21st century

class about Newton’s law of gravitation. You’ve carefully explained that the gravitational force depends on the product of the two masses involved and on the inverse square of the distance between them. You’ve shown a few examples or perhaps videos and animations to help your students connect the abstraction of an equation to the real physical world. You may assign thoughtful homework problems, and you encourage the students to ask questions if they don’t understand, either in class or during your office hours. You’re known as a good lecturer, and your students always rate you highly at the end of the term. Yet when you give your exam, you’re dismayed to see how many of them can’t answer straightforward questions of the type you covered in class and assigned as homework. So why does the same thing happen to instructors all over the country? Astronomy-education researchers have been working to solve that problem and many others facing instructors of astronomy survey courses for nonscience majors. Such courses are commonly called Astro 101. During a series of investigations conducted at the University of Arizona, education researchers have developed conceptual questions used to assess students’ understanding of core topics in such courses. Two of the questions are “At what location between the Earth and Moon does the net gravitational force on a spaceship become zero as it travels between the two bodies?” and “Would a waxing gibbous Moon ever be above the horizon during daytime?” After traditional lecture-based instruction, one student (Jennifer) stated in response to the gravity question, “halfway, because exactly halfway causes the Moon’s and Earth’s gravitational pulls to cancel out.” In response to the lunar-phase question, another student (George) answered, “No, because this phase only occurs when the Sun illuminates it during our nighttime.” Those responses indicate that after instruction Jennifer and George still had conceptual and reasoning difficulties common among their peers prior to instruction.1 By the second time Jennifer and George answered those questions, they had both participated in an interactive learning activity designed to help Astro 101 students confront common misconceptions. After completing the activity on gravity, Jennifer correctly answered, “Closer to the Moon than to Earth, because Earth has a greater force on the spaceship than the Moon does. But when the spaceship is closer to the Moon, Earth loses some force while the Moon gains some, until their strengths become equal.” And George was now able to correctly reason that “this phase is highest in the sky at 9 PM, therefore rising 6 hours earlier at 3 PM and setting at 3 AM. So yes, it would be visible for some short time between 3 PM and 6 PM in the daytime.”